A wide range of portable electronic devices currently available in the market, such as smartphones, tablet computers and the like, has been configured to support fast-response and human-centered applications. For this purpose, advanced processors and many sensing elements are employed in designing the portable electronic devices. However, since the advanced processors and sensing elements consume a high amount of power during the operation thereof, the portable electronic devices using them must be supplied with supplementary power from time to time.
Currently, there are two ways for charging a portable electronic device. In the first way, a battery inside the electronic device is charged by directly connecting the electronic device to an external power source via a transmission cable. In the second way, the battery in the electronic device is taken out and charged via a battery charger. In either way, a charger is needed. The charger is connected to a wall socket providing AC grid power, which is then converted by a transformer into a charging power source having a specific voltage level for charging the battery. However, for a user who works outdoors or is in an environment in which no power supply is available, it is impossible to immediately charge an electronic device that runs out of power. Moreover, for a completely sealed electronic device, such as an iPhone and an iPad, the battery is sealed in the device and can not be taken out, and the device must always be charged via a transmission cable. It is of course very inconvenient to do so.
The sealed electronic device is particularly inconvenient for use when it does not provide any connector or card reader slot with a USB interface. Under this circumstance, once the built-in memory in the electronic device is full, a user can not backup the data in the memory or expand the memory capacity but to delete some of the stored files.
To solve the power supply and memory expansion problems encountered by most portable electronic devices, various types of portable power banks and externally connected card readers have been developed. A portable power bank is a compact device for storing backup power supply and can be conveniently carried about for connecting to an electronic device to charge the same. With the portable power bank, an electronic device can be used at any place without the problem of running out of power. On the other hand, an external card reader is configured for a memory card to insert thereinto. When the external card reader is connected to an electronic device, the memory card inserted in the card reader can serve as an expanded memory of the electronic device or be used to backup the data of the electronic device.
Since the existing portable electronic devices all are designed to have small volume and low weight, they are usually provided with only one connection port for connecting to a portable power bank or an external card reader. That is, when the electronic device is connected to one of the portable power bank and the external card reader, the other one of them would not be able to connect to the electronic device at the same time.